Automotive transmissions

Abstract

A rotary transmission of continuously-variable-ratio type including a variator, that is to say a ratio-varying unit, and a subsequent gearing unit, the gearing unit being capable of alternative settings whereby the transmission may operate in two different regimes. The axes of rotary operation of the variator and the gearing unit are displaced from but parallel to each other, and the entire gearing unit lies between the two radial planes marking the axial extremities of the variator, which may be of the toroidal-race rolling traction type with two input discs located at opposite axially ends and a single, double-faced output member located centally between them, that member coinciding axially with the member of the gearing unit to which it is connected. The means of connection may be direct geared engagement, involving reversal of direction of rotation, or connection by chain, belt or the like involving no such reversal.

I claim: 
     
       1. A transmission of continuously-variable-ratio type including a variator, presenting an axis of operation and having an input and an output; a gearing unit, having components including not more than a single epicyclic combination comprising a sun member a planet carrier and an annulus, said gearing unit also presenting an axis of operation and having first and second inputs and output all coaxial with said axis of operation;   a final drive shaft, presenting an axis of operation and connected to said output of said gearing unit;   said variator output and input being connectable with said first and second inputs of said gearing unit respectively;   said variator also presenting first and second radial planes, relative to said axis of operation of said variator and marking the axial extremities of said variator; in which said gearing unit is capable of alternative settings whereby said transmission may operate in two different regimes in at least one of which a geared neutral condition is achieved in which said final drive shaft is at rest but said components of said gearing unit are under drive, in which said axes of operation of said variator and said gearing unit are displaced from but parallel to each other, and in which the entire said gearing unit lies between said first and second radial planes.   
     
     
       2. A transmission according to claim 1 in which said gearing unit comprises first, second and third mutually-rotatable components, arranged coaxially and in axial sequence along said axis of operation of said gearing unit, in which said first component is associated with said first input, in which said second component is associated with said second input, and in which said third component is permanently connected to said final drive shaft. 
     
     
       3. A transmission according to claim 1 in which said gearing unit contains a single epicyclic combination and first and second clutch-like devices, and in which said first and second clutch-like devices are operable alternately to cause said transmission to operate in either the first or the second of said two different regimes. 
     
     
       4. A transmission according to claim 1 in which said axes of operation of said variator, said gearing unit and said final drive shaft are located at the vertices of a triangle, when viewed in a direction parallel to said three axes. 
     
     
       5. A transmission according to claim 4, arranged so that said triangle lies in a vertical plane and said axes are all horizontal, the axis of said final drive shaft lowest. 
     
     
       6. A transmission according to claim 1 in which said variator is of the toroidal-race, rolling-traction type, comprising first and second input discs arranged at opposite ends of said variator relative to its said axis of operation, and a single, double-faced output disc constituting said output of said variator and located centrally between said first and second input discs. 
     
     
       7. A transmission according to claim 6 in which said output of said variator and said first input of said gearing unit are so connected that they rotate in the same sense. 
     
     
       8. A transmission acccording to claim 7 in which said connection is of the type including belts and chains. 
     
     
       9. A transmission according to claim 6 in which said output of said variator and said first input of said gearing unit are so connected that they rotate in opposite senses. 
     
     
       10. A transmission according to claim 9 in which said output of said variator and said first input of said gearing unit are both formed as gears, and engage directly.